lcd display , easy to operate on lcd screen multi stage charging (3-stage charging , parallel charging and equalized charging function) bts – battery remote temperature sensor terminal enable to charge li-thium, gel , lead-acid battery with rs485 & usb communication port protection: pv array short circuit, pv reverse polarity, battery reverse polarity, over charging, output short circuit dc load support and multi protection (for the 30amp series) mppt (maximum power point tracking)solar charge controller offer an efficient, safe, multi-stage recharging process that prolongs battery life and assures peak performance from a solar array. each charge controller allows customized battery recharging.